Method and apparatus for converting alternating or pulsating electric currents into unidirectional currents.



R. W. LOHNIAN.

METHOD AND APPARATUS FOR CONVERTING ALTERNATING 0R PULSATING ELECTRIC CURRENTS INTO UNIDIRECTIONAL CURRENTS.

APPUCATION Fl ED Y 1,143,213, L MA 22 mg PatentedJune15,1915.

THE NDRR/S PETERS CO1, PHOTO-LITHO.. WASHINGTON. D4 C.

UNITED s'rA'rns orme.

RALPH w.v rioni/LAN, or OAKLAND, CALIFORNIA.-

METHOD AND APPARATUS For. coNvEn'riNG ALTERNATING `on PULsArING nrincfrriic IcUnRNN'rs VIN'ro UNIDInncTIoNAL cURRnN'rs.

T0 all 'whom t may concern.' l

y.Be it known that I, RALPH W. LoHMAN, a citizen ofthe United States, residing at Oakland, in the county Vof Alameda and State of C-alifornia,have invented a new and useful Method and Apparatus for Converting Alternating` or Pul'sating Electric 'Currents .into Unidirectional Currents, of

which the following is a specification. in such full and clear terms as will enable those skilled in the art .to construct and use the same. f v A This invention relates to a method and apparatus for the production of i electric pressure waves of onecharacter from alter- 'na-ting' or' pulsating electric pressure vwaves of a different character.

In the drawings, in whichV the same numeral of reference is applied to the` same portion; throughout, Figure 1 is a vector diagram illustrating the resultant .rotating field occurring when two fields are lproperly compounded. Fig. 2 isa diagram ofA a series `of loops of .conductors placed in planes at 900 to each other and two conductorsadapted to revolve in proximity to said conductors.r4 vFig is a cross section of a 'machine `adapted to carry out the invention. Fig. 4 is a longitudinal section through said machine and Fig. 5 vis an enlarged detailedview of certainV parts, partly sectlOD. 1

several. million or more.

Vith apparatus lconstructed according to this invention uni-directional,V continuous, practically non-pulsating, or pulsating, dislcontinuous, or even `alternating electrical pressure waves, and havinga frequency the same or differing from those fed into Vthe machine, may be produced with well known voltage conversion ratios and veryhigh efficiencies when the said apparatus. is fed with single ,orv polyphase alternating currents or pulsating currents,.orr continuous currents, of any voltage from-.very low values, say fromO to 100, oreven less, to The conversion ratios mentioned=above are'those referring to the ratio of the effective to the maximum` value of an electrical wave and to the number and-method of connecting the applied source of such waves; that. is, whether theV machine/.is fed from a star Yor' delta connected and 2, 3, 6, or a phase source. l The above ratios do not refer to the term conversion ratio as-ordinarily'appliedto a Specification of Letters Patent. i Patented J une 15,1915.;

Application inea May z2, 1909. serial No; 497,634.

static transformer `(which ratio depends upon the relative number of turns -in-the primary and secondary), nor to the conversion ratio of an ordinary rotary converter TheY principles of the revolving electro magnetic field may be referred to here briefly for the-purposes of illustrating Athe above action..` If the direction and intensity of an electromagnetic field be represented by the direction and length of a line, then by .applying the` ordinary parallelogram rule for the compounding of vectors, the resultant of two fields thatdiffer in .direction and magnitude may be found by compounding the Yvectors representing them vvand drawing the diagonal. -Referringto Fig. 1, let OAxand OBfrepresent-the components which go through periodic changes with a constant. difference in phase; that is, if at any instant OAi represents the value vand direction of field A and, similarly OBZ-represents -the value and direction` of fieldV B, then OYLwill represent the direction; and magnitude of. the-resultant field, OY2 .and OY3 being' obtained in a like'manner.

Thus, if the variations of the two or more components follow the proper lawthe resultant may be caused to. change,` continuously uniformly in direction without changing in magnitude; or, in otherv words, 'two or more alternating vectors may be arrangedso as to produce astheirresultant a rotating vector of constant magnitude and uniform angular velocity. If nowreferring' to Fig. 2 A A and B.. B represent cross sections of t'wo'loops of conductors in' quadrature with eachother and two sine waves of. electrical pressure differing 4by 90 degrees from each other be passedthrough the respective loops AA and BB,a revolvioc ing electro-magnetic field as above described will be set up about the axis O.

If the magnetic permeability Yof the medium surrounding the conductors AA and BB is low, the magnetic field resulting will be correspondingly weak, while if the 'electrical pressure 0f the sine wave be relatively high and the circuits of conductors AA and BB be open circuited the 4electrostatic field will be relatively stronger than the electro-magnetic field, and will predominate, and will revolve in the same manner as the electro-magnetic field.

As is well known, there is a certain critical relation between the electrical pressure which may be applied to -a conductor and the radius of said conductor which may not be exceeded without causing the medium, depending upon the physical condition of said medium, surrounding said conductor to break down and form a conducting layer or corona therein. The term corona thus used signifies an velectrostatic discharge of high pressure, and of smooth or uniform texture, color and density. The term streamers indicates a more or less concentrated electrostatic stress as evidenced by longer or ropy discharges approximating long arcs. Thus, if two parallel and perfectly uniform conductors be placed in a uniform medium and subjected to a sufficiently high potential, a perfectly uniform glow without aics, sparks or streamers will become visible in the neighborhood of the conductors. If, now, points be affixed to the conductors, arcs, sparks or streamers will issue therefrom, because the electrostatic stress at these locations has been thereby increased beyond the rupturing gradient of the medium. The purpose of the points 18 in Fig. 4 isV thus to increase the electrostatic stress in their neighborhood and to facilitate and localize the production of corona at these particular points, for corona is not desired in the neighborhood of conductors 2aand 25, except along such parts thereof as are comprehended between the'extremities of conductors 13, 14 and 15. Also, to prevent arcs, sparks or streamer discharges from the points, if the voltage be excessive, they may be insulated by mica, glass, silica, porcelain or other suitable material of the proper thickness. 1f the voltage is not'sufiicient to produce such electrostatic stress in the neighborhood of the points and to rupture the surrounding air and if the air is not ruptured in the neighborhood of the points it will not be in the neighborhood of the larger conductors 21, 25, 13, 14 and 15) the points need not be so insulated or protected. Experimental work on a machine adapted to produce the conversions herein described sliow that by covering said parts with glass, mica or other insulating material of that characterthat it is possible to filter out the streamers or sparks and prevent the burning of said points.

Vhen corona is produced in air at atmospheric pressure, and if the voltage be `gradually raised above that required for initial corona formation, arcs or streamers are seen to appear within said corona or electrostatic'field and to extend from one conductor to the other. The presence of such arcs or streamers in this electrostatic held, produced for the purposes herein described, are undesirable and they may be suppressed or filtered out without affecting the true electrostatic field by surrounding one or all of the conductors with glass, or other suitable material, or with compressed air, 0r with oil, and such method of suppressing the arcing without affecting the electrostatic field desired, as described ab'ove, is deemed within the scope of this invention.

Referring again to Fig. 2 which is now intended to illustrate a resultant moving electrostatic field of uniform angular velocity and constant magnitude, if the con ductors a, Z1, be moved in synchronism with said field and if said conductors pass within said. conducting Zone, corona or field and are thereby caused to follow and be in actual electrical contact with the electrostatic potential therein by virtue of immersion in said conducting Zone or electrostatic field 0f constant magnitude, uni-directional, nonpulsating waves of electrical pressure may be obtained from combinations of such conductors by placing` suitable collecting devices on and near the terminals thereof. If the above mentioned conductors be caused to lag or lead periodically or otherwise with respect to the said electrostatic field, unidirectional, pulsating or other waves of varying pressure may be obtained and such method is also deemed a part of this invention. Or, if in the illustrated apparatus, the conductors a, b, be fixed, a single phase alternating pressure wave may be produced, said wave having the frequency of the pres sure waves in the conductors A A and B B. Again, if the conductors a, and be moved synchronously or non synchronously with the moving field, but said field is the resultant of two or more sine or other waves varying in phase relation with respect to each other, said waves producing a field of varying magnitude, or speed, or bot-h, the resultant rectified pressure wave in conductors a and Z) will also vary in inagnitude although not in direction and pulsating or other non-uniform waves of pressure may be obtained therefrom.

If the conductors a and be moved at a greater or less speed than, and in the same or the opposite direction from the movement of the resultant field, an alternating current of a frequency corresponding to the relative velocity of the conductors and said i I lield willbe produced.

The above sketches, while indicatingonly -a two phaseldisposition of primary or stationary conductors (AA-43B) and a single pair of.. secondary `or moving conductors (ca -b), thereby making it possible toobtain only single phase or single sets ofpul- .satingor non-pulsatingwaves therefrom, is Y presented' only to simplify theillustrations.

vAny number of sets of primary and -secondary conductors properly disposed with -relation to each other and thereby Vmaking it possible to apply 2, 3, or @phase pressure waves, `or any multiple' thereoftmthe primary and to obtain single or multiphase pressure waves, alternating, pulsating, unidirectional or continuous from the secondary, as. described elsewhere, areto be considered as a part of this invention. Or, if

the machine is fed `with continuousV unidirectional current, and conductorsrnb, are .rotated within such lield, valternating orpulsating waves maybe obtained therefrom.Y

Having described the principle' involved,

which consists briefly in-moving or holding fixed, a conductor, or conductors,jwithin *a ,moving 'or stationary electrostatic yconducting field', yand thereby maintaining actual electrical connection therewith 'and obtainv ing therefrom waves of electrical-pressure, one form of apparatus to carry out the invention and method may here be described. *y The numeral (v1). represents asuitableV drum of such strength as may be deemed necessary' for: given conditions, said drum being provided 'with lagging' ory insulation (2) if desired. The lends of the drumfare .provided withheads (3) suitably stifene'd with ribs (4), said heads carrying bearings yConductors (13) (14) 2Mid (15)arevinouiit-V ed yupon suitable insulatorsV and pins as i `shown at (16) and (17) andcarry suitable o devices (18)' in order to increase the electrostatic density in their neighborhood .and throughout the conducting yfield and thus produce the desired conductivityV of the corona in the surrounding Vmedium; ,and (19) represents some material asglass, mica ,or other suitable material surrounding the conductors and adapted to withstand the heating andl other effects consequent upon the passage-of the electrostatic corona and to permit `the passage thereof, but to prevvent'the passage ofiarcs or streainers.

.Secured to the shaft (20) are four insuvlating members '(21)'r two' of which' carry slip rings or conductors"(22) and (23) of `suitable shape u on their periphery. AAc- .tive conductor `cally to vcollector (22) and active conductor 24) is connected electri- (25) is connected electrically to collector (23). .Said active conductors (24) and (25) having a similarset of devices (18) to those vof active conductors (13) v (14) and (15).

Insulating supports (26) yare provided adapted to carry brushes or other collecting devices (27).l And conductors (28) and (29) lead from said brushes through insulating bushings (30) and (31). Y i

(32) represents a synchronous motor or ,other suitable device for rotating the shaft (20) at any desired speed;

Since it may be desirable to vary the radial distance between active conductors (13) A(14) and (15)- and (24) and (25), suitable adjustments (33) are provided whereby this may be accomplished,and by varying the distance between the `liXed and" rotating active conductors the machinemay be opervated throughout `vwide rangesl of voltage,

even with constant` air pressurein the drum.

`(34) represents a suitable pipe connection for conductingY air to the interior of the drum and(35) a gage to indicatethe pressurev therein.

field will be set up about the shaft (20) and if the conductors mounted on said shaft are rotated by any suitable means in synchronism, or otherwise, as has been set forth herein, there will be a rectification ofthe three phase current fed to the'machine in ythe manner described herein, provided the 1 voltage used, the distance between the ro-V tating and iX'ed conductors, thicknessV of the medium (19), and the air pressure, Vare suitably .controlle If a three phase current of greater or less If,`,now, the leading-interminals) and V(9) be connected toa high pressure '.threephase source a revolving electrostatic voltage is to be connected to the leading-in conductors, in order to render the-device operative itis only `necessary tochange the distance between the revolving and Xed conductors, or the air pressure, or the geometric shape of the devices (18), or thev thicknessof the medium (19). In other words any-combination of electric pressure in the lield and atmospheric or mechanical pressure onl the surrounding medium may be provided for as above, inorder to vprevent the disruption of the surrounding conducting medium, or for the purpose of'limiting the'extent and density of the corona.

While the above description ofthe apparatus'mentions lonly a three phase conversion apparatus.;` z'. e. one adapted to receive three phase alternating current and deliver direct or'continuous current, the luse of suitable designs for and Vinvolving thereception on the incoming side of polyphase 'currents of any character, single phase or Apulsating currents, or direct or continuous currents, and the delivery from the apparatus of the corresponding transformed direct or alternating or pulsating currents, or waves of electrical pressure, are also deemed to be within the scope of this invention. Such incoming alternating currents need not bear constant phase relation to each other,

`nor is it necessary that they be of equal magnitude and they may have different maximum and intermediate values.

Having thus described my invention what I claim as new and desire to secure by Letters Patent of the United States is as follows: such modifications as come within the `scope of the claims being expressly reserved.

1. A method of converting electrical pressure waves from one form into another form, which consists in maintaining a moving conducting electrostatic field or corona,

fluence .of said field, and withdrawing current from said conductors, substantially as set forth.

3. A method of converting electrical pressure waves from one form into another form, and controlling the character of the discharge, which consists in maintaining a rotating electrostatic field or corona, subjecting an electrical conductor to the infiuence of said field,` suppressing undesirable arcing by controlling the' pressure on the fluid in which said corona is foi'med, and withdrawing current from said conductors, substantially as described.

4i. A method of converting electrical pressure waves from one 'form' into another form, and Vcontrolling the character of the discharge, which consists in maintaining a rotating conducting electrostatic field or corona by means of such waves, suppressing undesirable aicing by controlling the pressure on the fluid in which said corona is formed, subjecting electrical conductors to the influence of said field or corona, and withdrawing current from said conductois, substantially as set forth.A l

' 5. A method of convertingelectrical presT sure waves from one ferm into another form, which consists in maintaining a rotating conducting electrostatic field or corona by means of alternating electrical pressure waves moving electrical conductors within said field or corona, and withdrawing currentfrom each conductor, substantially as set forth.

G. A method of converting electrical pressure waves from one form into another form, which consists in maintaining a rotating conducting electrostatic field or corona by means of an alternating electrical current, moving electrical conductors synchronously with said field, and withdrawing current from said conductors from said corona, as set forth.

'7. A method of converting electrical pressure waves from one form into another form, which consists in maintaining a rotating conducting electrostatic field having a uniform angular velocity, moving conductors in and synchronously with said field, and withdrawing current therefrom, as set forth.

which consists in maintaining a rotating conducting'electrostatic field having a uniform Vangular velocitv by means of alternating currents, moving conductors at a determinate position in and synchronously with said rotating field, and withdrawing current therefrom, as set forth.

' AV method of converting electrical pressure waves from one form into another form, which consists in maintaining a rotating conducting electrostatic field having a substantially constant' magnitude by means of an alternating electric current; rotating conductors at a determinate position in and synchronously with said field, and withdrawing current from each of said conductors, substantially as described.

10. In an apparatus of the described class, the combination of a series of conductors adapted to produce and maintain a rotating, conducting electrostatic field when fed with the proper current, means t-o increase the density of the field in the neighborhood of the conductors, conductors adapted to be subjected to the infiuence of said field, and means to withdraw current continuously from said last-mentioned conductors, substantially as set forth.

11. 1n an apparatus of the described class, the combination of a series of conductors adapted to produce and maintain a ii'otating, conducting electrostatic field when fed with the proper current, means on the surface of said conductors to increase the density of the field produced, revoluble conductors adapted to be subjected to the influence of said field, and means to withdraw current continuously from cach of said revoluble conductors, substantially as set forth.

12. In an apparatus of the described class, the combination of a series of conductors adapted to produce and maintain a conducting electrostatic field when fed with the proper current, a member revoluble adjacent said conductors, non-conductorscarr1ed by said member, conductors carried by said non-conductors and collecting devices adaptthe proper current, 'a revoluble member lying substantially in the axis of the said conductors, conductors carried by said' revoluble member and adapted to be moved in said iield, and non-conducting envelo-ps surrounding the several Vconductors and means to withdraw current fromthe moving conductors, asset forth.

14. In an apparatus of the described class,

the combination of a series of conductors adapted to produce and maintain a rotating conducting electrostatic field when fed with the proper current, a drum adapted to contain fluid at any desired'pressure, and in which said conductors are placed, a revoluble member having substantially the same axis as that of the eld, conductors carried by said revoluble member, and adapted to be revolved. in proximity to the first-mentioned conductors, as set forth.

15. In an apparatus ofthe described class, the combination of-a drum adapted tocontain fluid at any desired pressure, conductors in said drum adapted to produce and maintain a rotating conducting electrostatic field when fed with the properv current, a revoluble member having substantially the same Aaxis as that of said field, conductors carried by said member and adapted to be revolved in proximity to the first-mentioned conductors, non-conducting envelops for the several conductors, and means to withdraw current from the conductors on said revoluble member as set'forth.

16. In an apparatus of the described class, the combination of a drum adapted to contain a iuid at any desired pressure, insulators carried by said drum on its interior, conductors carried by said insulators spaced from the drum and adapted tomaintain a rotating conducting electrostatic field when fed with the proper current, a revoluble shaft passing substantially through the axis of said drum, insulators on said shaft, conductors carried by said insulators, non-conducting envelops for the several conductors, means to rotate the shaft synchronously with the field and collecting devices at the end of each revoluble conductor, as set forth.

17. In an apparatus of the described class lthe combination of a drum adapted to contain a fluid at any desired pressure, insulators carried by said drum on its interior, conductors carried by said insulators and symmetrically placed, av revoluble shaft passing through said drum, insulators on said shaft, and a pair of conductors carried by said insulators, a current collecting device for each of said latter conductors, and means to rotate said shaft at any desired rate, as set forth.

18. The method of rectifying electric currents which consists in producing successive positive corona discharges from a plurality of electrodes, subjecting a conductor successively to the positive corona discharges and withdrawing direct current from said conductor.

In testimony whereof I have set my hand this fteenth day of May A. D. 1909, in the presence of the two subscribed witnesses.

RALPH W. LOHMAN. vWitnesses:

C. P. GRIFFIN, A. K. DAGGETT.

Copies of this patent may be obtained for ve cents each, by addressing the Y Commissioner? 0f Patents, Washington, D. U. 

